A recent innovation in elevator technology is to save space utilized for elevator hoistways, instead of for rental or other beneficial use, by having two or more elevators operating within the same hoistway. In order to maximize the benefit derived therefrom, the elevators must move as freely as possible while maintaining suitable separation. In order for this to occur, there must be communications of operational data, either directly between the several elevators in the single hoistway, or between each of them and a central controller. Due to the amount of data, and the frequency with which it has to be updated, hard wiring each of the cars to the other, or to a common controller, will not effectively communicate the required operational data. Therefore, communication networks such as Ethernet or CAN are used in a typical case. However, communications of this sort are subject to failure, due to hardware breakdown or disconnection, disruption to power supply, noise or otherwise.